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  1.    #1  
    I'm getting 500ms or so ping time to www.yahoo.com. Sometimes it goes as high as 2000-3000ms for the frist few packets. Does this seem high to people.

    FYI, nice freeware ping program:
    http://www.handango.com/PlatformProd...0&platformId=1
  2. #2  
    Did you do a tracerte to check the path to Yahoo? How many retrys on how many nodes?

    Gary
  3. #3  
    Working with wireless technology has alot of latency, it has to transmit to the cell tower, which can be miles away then it has to send the data out through the cell tower base station to a server, which then gather the requested info from the net. This increase the ping time which can be a over 1 sec
  4. #4  
    Originally posted by Sprint Tech
    Working with wireless technology has alot of latency, it has to transmit to the cell tower, which can be miles away then it has to send the data out through the cell tower base station to a server, which then gather the requested info from the net. This increase the ping time which can be a over 1 sec
    Excellent response! And if there is a weak signal anywhere in between origin and destination it only exacerbates the problem.

    Gary
  5. #5  
    But I thought radio traveled at the speed of light which would be, let's see, 186,000 miles per second. Some of you make it sound like a cell tower miles away should take a while to reach. I'd have to disagree on that. Then you have the cell tower base station to the net. That's got to be good for another couple of hours.

    I think we are skirting the issue that packetizing the data allows latency but does not necessarily necessitate latency if that makes sense. Internet ping times require less retrys. I think the key here is to focus on analysis of retrys. Usually the first few packets require the routers involved to establish the route but then the route get cached and subsequent attempts are faster. Only my opinion but it seems to fit my observations.

    Me thinks the achilles heel is in the air between your phone and the cell site. The rest can be landlines such as fiber, copper T1s, DS3, etc. Personally, I'm hoping the new "2.9G" technology will yield improvements in this area.

    A subject matter expert on the radio side of this technology would really add some factual value. In other words, what's really "new" here that justifies TV ads showing streaming video and online games.
  6.    #6  
    I just ran it now. 300-500ms, no retries. sorry, I don't have traceroute for the palm. any idea where I could get it? Or I could run a traceroute from my home machine to thepalm if I could figure out what the palms ip address is. anyone know how I can do that?
    I will note that the speed of light from my palm to the tower can't be the limiting factor
  7. #7  
    Originally posted by work_permit
    I just ran it now. 300-500ms, no retries. sorry, I don't have traceroute for the palm. any idea where I could get it? Or I could run a traceroute from my home machine to thepalm if I could figure out what the palms ip address is. anyone know how I can do that?
    I will note that the speed of light from my palm to the tower can't be the limiting factor

    Tain't the speed of light. But ... if one is in a weak signal area, say right on the ragged edge, the retry rate can and will very quickly affect data rate, or throughput. Weak signal areas will cause the modem side of things to re-negotiate bits per second down to a more reliable, slower, bits per second.

    Weak signal areas ---

    1. You're to far from the cell tower. Move closer.
    2. You're standing in a natural NULL. Move left or right 6 inches.
    3. The signal has a bounce off a nearby metal, or other reflective surface. Move.
    4. You're in J. C. Penny's. Steel reinforced concrete. Go outside.
    5. You're standing under very noisy power lines that are blowing out most of the spectrum. Move.
    6. The celluar network hates you. SOL.

    Gary
  8.    #8  
    I do agree that a weak signal could degrade performace. I have tried this with full bars on signal strength, and seem to get same 300-500ms ping time. Also, I'm getting no retries.
  9. #9  
    Maybe it's possible that full bars is a lousy signal but it just happens to be as good as it gets. Still waiting for someone to tell us what the 2.9G technology has improved when it comes to the cellular part.
  10. paz5559's Avatar
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    #10  
    OK, let's start with basics -- it is speed of SOUND, not speed of light. Speed is variable depending on how far you are abouve sea level, but tends to be about 650 mph.
  11. paz5559's Avatar
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    #11  
    Also, in addition to signal strength, speed is also dependant on the number of others on the node at the same time as you. Don't forget, this is a shared bandwith, and voice is given priority, so data only gets the leftovers, regardless of the number of bars you see on your handset
  12.    #12  
    OK, let's start with basics -- it is speed of SOUND, not speed of light. Speed is variable depending on how far you are abouve sea level, but tends to be about 650 mph.
    I don't think you mean that my cell phone is communicating with the cell tower at the speed of sound, are you?
  13. #13  
    Originally posted by paz5559
    OK, let's start with basics -- it is speed of SOUND, not speed of light. Speed is variable depending on how far you are abouve sea level, but tends to be about 650 mph.
    Radio communicates at the speed of sound ? That explains the latency. Is wagering allowed on this board ? Agree that there are tons of factors like number of users, reflections, null spots, competing noise, steel renforced concrete, mountains, dirt, etc. but I sure hope we are starting with something faster than the speed of sound.

  14. #14  
    Actually, the packets of data are distributed evenly and dropped on the hood of cars going down the road which explains why the latency seems to be worse during rush hour traffic, and why you get a busy when there is an accident and everybody is calling to say they will be late.
  15. #15  
    LOL!

    Speed of sound, that's a good one.

    I can assure you that radio is in the electromagnetic spectrum, same as light, X-rays, etc... Sound happens because molecules bounce against each other, causing a pressure wave that your ear hears. The speed of sound is slower at higher altitudes because there are less molecules.

    However, radio is energy, not pressure waves, otherwise radio would not work in space! But I like the idea of it!

    Could you see radio/cellular moving at the speed of sound? Pilots moving at 400 miles per hour away from the airport would have to be patient because the tower would have to wait for the signal to arrive, etc...

    I do believe the packets are affected by traffic, huh, network traffic that is...

    There are many factors that can change the latency. How many layers are we really going through, each adding a few ms? There's the tower, there is something between the tower and the land line, there must be some type of IP server, etc... Even if a traditional traceroute does not show it, I bet there is a ton of equipment handling the call. Is there an expert around that can tell us?

    -Jerry
  16. #16  
    Originally posted by paz5559
    OK, let's start with basics -- it is speed of SOUND, not speed of light. Speed is variable depending on how far you are abouve sea level, but tends to be about 650 mph.
    Heh.

    Yeah .... when I have to yell out my window at the cell tower 'cause i can't make a call ..... then it's traveling at the speed of sound.

    Otherwise, light it is.
  17. #17  
    Ok, I don't know if this will work or not ... but here's a thought ... does each 3G Treo have its own routable IP address?

    I have a hunch that everything is probably going through some sort of NAT which would prevent this from working. But ...

    1) If you had a real IP address and could determine it in blazer by going to http://whatismyip.com ...

    (note ... if multiple people try this and all end up with the same IP address ... that points to a common NAT gateway handling everything)

    2) You could leave your phone logged in to "data mode" or whatever it is you 3G'ers call it ....

    3) You could ping/traceroute directly to your phone from your desktop and see where the latency is kicking in

    Just out of curiosity, I think I'll go try this on my Treo 270 with CSD and see what happens ....

    Ah. Actually, you'll need to use something other than Blazer or Xiino. When I tried it with Blazer, I got the IP address of 64.75.2.10 which resolves to blazer-fetch.handspring.com. Xiino was at 210.128.156.102. Even in my traceroute to those addresses, I saw a couple of nasty latency stats ... 2500ms on one of them to Blazer, and some really bad ones to Xiino.

    So, the Blazer servers might not have very good latency. And of course, the Xiino servers are in Japan.

    Hmmm ... thinking. Eudora would work. It doesn't go through a proxy, right? I don't feel like installing it....

    Anyway ... just some thoughts. If you can't test latency from A->B, test it from B->A.

    -Doug
  18. #18  
    Originally posted by dtoombs
    (note ... if multiple people try this and all end up with the same IP address ... that points to a common NAT gateway handling everything)
    Well, not necessarily NAT. Browsers like Blazer and Xiino use proxies that mangle the HTML before returning it to the PDA, so we're not just talking about simple NAT (though that could be in place as well).

    Anyway ... just some thoughts. If you can't test latency from A->B, test it from B->A.
    Good thinking, but don't forget that on IP routed networks, routes are not necessarily symmetrical. The routing from A->B may go through quite a different set of hops than B->A. Tracing "backwards" may give you misleading results.

    Actually the only way to get the full picture on latency is to do a traceroute from A->B and a traceroute from B->A (meaning you need an account on server B, or you need IP source routing to work, which it usually doesn't) and then compare.
  19. #19  
    BTW, 500ms ping times seem to be average that people on the Verizon 1xRTT network are getting as well, but from what I've read, those folks are getting the full advertised bandwidth (unlike with Sprint, it would seem) -- it's just that the latency is too high for sysadmins to use for realtime connections like SSH or Windows Terminal Services. Reportedly it's just great for email and web, though.
  20.    #20  
    Good idea on eudora, as you note the other browsers go through proxies.
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